for循环,while循环,do while循环是否可以互相替代呢?

Original 2019-04-15 16:06:30 1071
abstract:<!DOCTYPE html> <html>     <head>         <meta charset="utf-8">      &
<!DOCTYPE html>
<html>
    <head>
        <meta charset="utf-8">
        <title></title>
        <style type="text/css">
            
        </style>
    </head>
    <body>
        <input type="checkbox" id="checkall" onclick="checkAll()"><lable for="checkall">全选</lable>
        <hr>
        <input type="checkbox" name="item[]">选项1<br>
        <input type="checkbox" name="item[]">选项2<br>
        <input type="checkbox" name="item[]">选项3<br>
        <input type="checkbox" name="item[]">选项4<br>
        <input type="checkbox" name="item[]">选项5<br>
        <input type="checkbox" name="item[]">选项6<br>
        <input type="checkbox" name="item[]">选项7<br>
        <input type="checkbox" name="item[]">选项8<br>
        <input type="checkbox" name="item[]">选项9<br>
        <input type="checkbox" name="item[]">选项10<br>
        <br>
        <p>分别使用for循环,while循环,do while循环做了全选的案例,都可以实现效果,那么这三种循环语句是否可以互相替代通用呢?</p>
        
        <script type="text/javascript">
            /* function checkAll(){
                var checkall , item;
                checkall = document.getElementById('checkall');
                item = document.getElementsByName('item[]');
                
                for(var i = 0; i<item.length; i++){
                    if(checkall.checked){
                        item[i].checked = true;
                        
                    }else{
                        item[i].checked = false;
                    }
                    
                }
            } */
            
            /* function checkAll(){
                var checkall , item;
                checkall = document.getElementById('checkall');
                item = document.getElementsByName('item[]');
                var i=0;
                while(i<=item.length){
                    if(checkall.checked){
                        item[i].checked = true;
                    }else{
                        item[i].checked = false;
                    }
                    i++;
                }
                
            } */
            
            
            
            
             function checkAll(){
                var checkall , item;
                checkall = document.getElementById('checkall');
                item = document.getElementsByName('item[]');
                var i=0;
                do{
                    if(checkall.checked){
                        item[i].checked = true;
                    }else{
                        item[i].checked = false;
                    }
                    i++
                }while(i<=item.length);
            }
            
        </script>
    </body>
</html>


Correcting teacher:查无此人Correction time:2019-04-16 09:55:27
Teacher's summary:完成的不错。想到问题,可以自己动手测试下。我回答你可以,那你还是不知道怎么写的。继续加油。

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